This invention relates to the art of electrochemical cells and more particularly to a new and improved electrochemical cell and cathode therefor comprising a Group IA metal anode and a composite metal/metal oxide or metal oxide cathode.
Light metals have exceptionally high energy density when employed as the anode material in electrochemical cells owing to their low atomic weight and high standard potential. This high chemical activity of light metal anode material requires the use of a nonaqueous electrolyte and a cathode which meets the rigorous requirements for such a cell. Most cathode materials are too readily soluble in a nonaqueous electrolyte, and thereby reduce the useful capacity of such an electrode after storage.
It is known to use metal oxides, particularly heavy metal oxides, as cathode materials in nonaqueous electrochemical cells. For example U.S. Pat. No. 3,945,848 discloses the use of cobalt (III) oxide, U.S. Pat. No. 4,158,722 discloses a cell employing a chromium oxide cathode, and U.S. Pat. No. 3,423,242 discloses a cell employing a vanadium pentoxide cathode.
A continuing problem encountered with these and other cells having metal oxide cathodes is the relatively low discharge potential and consequent low energy density. Additionally, as noted above, the appreciable solubility of the metal oxides in the nonaqueous electrolyte leads to a metal deposit on the anode after extended storage, thereby causing a loss of capacity.